Field of the Invention
The present invention relates to a network service continuity technology, and more particularly to a system and a method for service continuity in heterogeneous wireless networks.
Description of the Prior Art
Generally speaking, most of the applications in network devices cannot handle the changes in network connectivity during the handover procedure. For example, when a network device moves to a new location and changes its point of network attachment, network connections on the devices may be terminated or suspended, and the user may need to resume network services manually. This disconnection and manual reconnection may degrade the service qualities, thus resulting in bad user experience.
Moreover, network devices nowadays usually can utilize different types of networks (e.g., 3G and Wi-Fi) and transmit data through a plurality of paths in heterogeneous networks, wherein a path is a connection of an Internet IP address on the network device to another Internet IP address on a corresponding device. For example, if the data was initially transmitted through a Wi-Fi network and the Wi-Fi network signal has gone weak, then the data could instead be transmitted through a 3G network. For another example, data can be transmitted through the 3G network along with the Wi-Fi network concurrently to increase the efficiency of data transmission.
However, switching wireless interfaces may disrupt or, even the worse, terminate the data transmission of the ongoing communication sessions of network devices. Furthermore, concurrent data transmission through a plurality of paths may introduce out-of-order data reception in the receiver end due to the diversity of bandwidths, delays and reliabilities in heterogeneous wireless networks. Such out-of-order data reception may seriously degrade the efficiencies of data transmission with multiple wireless networks.
Take the US patent application No. 2009/0113539 for example. The patent disclosed a gateway system for implementing access to various media, wherein the gateway system includes a handover decision module. Accordingly, the communication media access module of the gateway system enables, through cooperation with the media independent handover function (MIHF) module and the handover decision module, the user equipment (UE) in the local area network (LAN) environment to accomplish media independent seamless handover, so that uninterrupted access to the service network subsystem domain is achieved. However, in the architecture, all the application programs of the devices in the LAN have to use connections with the same quality. Even if the devices or the programs have requests for different quality of service (QoS), they are still forced to use connection with the same quality. Moreover, the architecture of the patent cannot support the delivery of cross-layer events. As a result, the application programs cannot acquire the information of the link layer, so as not to optimize the behavior of the application programs according to the information of the link layer.
On account of above, the present invention proposes, for the professionals in the field, a system and a method for devices to utilize multiple heterogeneous wireless interfaces effectively in accordance with the application requirements and the network conditions.